Defi is better than traditional finance because it returns asset ownership and all rewards associated with it to the true owner (you) of the assets.
In traditional finance, you lose the benefits offered by YOUR MONEY by parking it at a bank. The bank loans out YOUR MONEY, reaps all the rewards, and might give you 0.1% of the 6% or 8% in interest income they receive from YOUR MONEY, if you are lucky. In traditional finance, you also lose the benefits of other assets like YOUR STOCK by parking it at a brokerage. A brokerage does the same thing and loans out YOUR STOCK to hedge funds who dump it on the market and wreck the price. The brokerage reaps all the rewards from loaning out YOUR STOCK and usually gives you nothing.
In defi, you own your assets. You become both the bank and the brokerage and you reap ALL of the benefits and rewards that your money and your other assets offer.